The great thing about melodicas is that everything is in miniature. So you only need very small amounts of wood for your keyboard. I chose 2 types of ebony, neither of which are endangered. Demand is highest for pure black ebony (as traditionally seen on piano keys), but I prefer the more colourful examples, which have just the same hardness and strength
Here’s the raw materials. This will soon be a keyboard!
I think you are going to get a lot of miles out of 3.5 MM. Is that about double the thickness of the piano veneers you used last time?. By the way, what materials did you use for the reeds and plates you had made?